Actually looking at that circuit I would expect it to increase the noise in your filter!
Quickly plug in the 20uf and see what happens! Should only take a few seconds.
If that doesn't have any effect we can talk about ways to keep the filter but block the noise.
In noise control we consider the source, the path and the receiver. So if the source can't be fixed, you could try either cotton or ice-picks in your ears! But ruling out that approach leaves the path.
A thin rubber gasket where the filter mounts will provide a slight decoupling to the chassis. The best material for forming a shield wall is lead. You can actually buy lead foil for this purpose. But for a simple try wrap the filter with a thin piece of rubber and wind 2 layers of .062" solder around that.
At one place I was staying the HVAC noise was so loud it kept me awake at night. My meter said it was 55dba (75dbc) at my sleeping position. The management actually had the service company replace the problem motor. The level only dropped to 45dba. But that was enough!
So depending on how loud the noise is, may affect how much you need to do.
Best of luck to you!
The same sort of measurement were put on this link in the past. Why should I just put up similar measurements? They are already here. SY saw these sort of measurements made with his own eyes, yet he has ignored them.
PMA, there is no conspiracy on my part, at least, what would be the point?
PMA, there is no conspiracy on my part, at least, what would be the point?
Pavel.
After all the discussion about personalizing an argument...
Yes John is a flaming "A" type personality. He knows, so do we. When I review the threads, I find there is a ton of useful information which I have never seen before.
As a result I post things I think are hidden and useful. These may be off topic, but it is my way of playing in the same sandbox. I will not tear down John's sand box castle.
When NASA put men on the moon, they went to ridiculous lengths to do it. Many of the hard to do tweaky items, showed the way to do many, many things better.
ES
Except when the same cables were measured using an Audio Precision System 2 Cascade, measuring better than 20dB below where you were measuring, no distortion was found beyond the AP's residual distortion.
Cable Measurements
Did you bother to show your associate the AP measurements?
Somehow I doubt it.
se
That was done by Bruno Putzeys using an Audio Precision System 2 Cascade. See the measurements above.
se
For some reason, Audio Precision does NOT measure what I measure with my Sound Technology equipment. Please remember the grounding is different, and this MIGHT explain why, but for ME the distortions always appear, at least until the cable is used a lot (break-in?). For example, I have one well used RS cable, that I use for testing, and it measures OK. I have two other RS cables, not often used, and they measure lousy. Go figure. Now, should we BELIEVE ONLY in AP, because it can measure somewhat lower in level? Is the AP grounding and balanced drive, UNIVERSAL in its practical similarity to a typical audio set-up?
If my comments appear to be targeting JC it is because he appears to me to be the most articulate and knowledgeable proponent here of a point of view I take strong exception to.
I am in no way interested in his personal life or personal history, they are not relevant to these arguments. However, there are times when his statements and conclusions seem to me to be inconsistent with his scientific training.
I am also not interested in arguing the merits (or lack of them) of his work products, for all I know they may be exemplary for their type.
If I believe that there are technical faults in his statements I will not hesitate to express my views. I'm also not inhibited in discussing the wider picture into which individual issues or instances exist as looking at the forest and not just the trees puts the trees in more meaningful context. For example, his recent statements about wires will need far closer scrutiny to determine what they mean. My own tests have led me to conclude that whatever distortions the inexpensive wires he disdains may produce, they are not relevant to issues related to home sound reproduction. For example, in the signal path of an NTSC video signal with over 300 times the bandwidth of an audio signal, they made no detectable difference. I'll wait to see what he has to say about those measurements that elicited a "wow." The last time we had this discussion, the issue was between the difference between the best and the worst being the difference between minus 120 db down and 135 db down of the noise of the seventh harmonic of 5 khz. Will this wow be like that one was? If I had any lingering doubts at the time, he convinced me that the cheap ones he disdained were more than adequate for home sound systems.
Can I ask what you attribute these lousy measurements to on one cable versus the other?
Are we talking about quality of materials, geometry, shielding/no shielding, terminations, connectors, etc......
Have you varied the amplitude and frequency of the signal through each cable you're measuring, and if so, what has been the result?
What about C/L/R measurements for each cable? Similar, completely different?
What about a "burn in" type of situation, initial measurements versus after 12 hours of "burn in"?
Also, and maybe this is naive, but what about tempeture differences.
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Don't bring old fights here.
A sound suggestion, that most likely will be disregarded.
Getting back to college in 1963-64. I was very surprised at what PHYSICS was, once I was enrolled in upper division. Lower division was much the same for EE and Physics, but upper division (second 2 years of college) was daunting, in physics. Had I not met a certain physics professor, who gave me a pep talk, I might have dropped out completely.
In any case, I finished my junior year, studying physics, and I am glad that I did.
However, I dropped out of college for a second time, because I KNEW that physics was not what I was really interested in. Remember, electronics, that I did so well in high school with almost 5 years earlier. At this time, I had not taken ONE course in electronic design. Calculus, physics, chemistry, yes, but NO circuit design.
I therefore tried a self-study program, moving to Berkeley, with its intellectuals, and book stores, and taking a few night courses in electronic design. I got a job or two as an electronic technician, as well, and learned for example, resistor color code by sorting out piles of resistors placed at random, in front of me. (useful stuff)
After about a year of sorting things out, I decided to finish college, as I found that getting a job, at my experience level was difficult, as I was not considered an 'indian' (tech) or a 'chief' (engineer).
In any case, I applied at a third college and they told me that IF I wanted to get out of college quickly, I should finish in PHYSICS, but they would let me take EE courses (jr year) as a minor. So, I did what I had to do, and it almost killed me to do it.
However, on graduation, I was immediately picked up by Friden to work with computer aided design, and product development, and MY education as an 'engineer' began.
First, I worked with 3 excellent engineers. The best guy did NOT have a college degree, but he was able to prove that our computer simulations were giving us the wrong results, and he did it with ONLY a slide rule. I think that he was a 'natural'.
The other two were OK to very good. One taught me how to use the Tektronix test equipment and circuit design in general, the other was in love, as I was, with computer simulation of electronic circuits. Both ended up, years later, as senior engineers at Lawrence Livermore Labs. It was a wonderful year, and I learned a lot, especially by spending my lunch hours in the company technical library. That is where I learned to parallel transistors and jfets to get lower noise, in an obscure and expensive journal in early 1967.
Moving on, I applied for a job at Ampex. There, I hit pay-dirt again, working under a couple of guys who later became professors of engineering. Doing their dirty work, such as extended calculations, in exchange for REAL engineering insight. more later
In any case, I finished my junior year, studying physics, and I am glad that I did.
However, I dropped out of college for a second time, because I KNEW that physics was not what I was really interested in. Remember, electronics, that I did so well in high school with almost 5 years earlier. At this time, I had not taken ONE course in electronic design. Calculus, physics, chemistry, yes, but NO circuit design.
I therefore tried a self-study program, moving to Berkeley, with its intellectuals, and book stores, and taking a few night courses in electronic design. I got a job or two as an electronic technician, as well, and learned for example, resistor color code by sorting out piles of resistors placed at random, in front of me. (useful stuff)
After about a year of sorting things out, I decided to finish college, as I found that getting a job, at my experience level was difficult, as I was not considered an 'indian' (tech) or a 'chief' (engineer).
In any case, I applied at a third college and they told me that IF I wanted to get out of college quickly, I should finish in PHYSICS, but they would let me take EE courses (jr year) as a minor. So, I did what I had to do, and it almost killed me to do it.
However, on graduation, I was immediately picked up by Friden to work with computer aided design, and product development, and MY education as an 'engineer' began.
First, I worked with 3 excellent engineers. The best guy did NOT have a college degree, but he was able to prove that our computer simulations were giving us the wrong results, and he did it with ONLY a slide rule. I think that he was a 'natural'.
The other two were OK to very good. One taught me how to use the Tektronix test equipment and circuit design in general, the other was in love, as I was, with computer simulation of electronic circuits. Both ended up, years later, as senior engineers at Lawrence Livermore Labs. It was a wonderful year, and I learned a lot, especially by spending my lunch hours in the company technical library. That is where I learned to parallel transistors and jfets to get lower noise, in an obscure and expensive journal in early 1967.
Moving on, I applied for a job at Ampex. There, I hit pay-dirt again, working under a couple of guys who later became professors of engineering. Doing their dirty work, such as extended calculations, in exchange for REAL engineering insight. more later
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JC is certainly not a caged animal, he is a mature man with the skill to defend his points of view.
His statements vary widely from the topic of his "blowtorch preamplifier" as his recent comments about wires and loudspeakers prove. Are you and brianco suggesting that responding to those comments are off limits? Why? Or are you suggesting that this place should be his private soapbox from which to pontificate?
I don't know the latest AP models, but the previous ones had transformer balanced floating output with selectable grounding.
In principle yes. In practice, not at the current state of the art. Both the acoustic models and measurement devices are too primitive to fully understand and measure acoustic fields in a meaningful way. So is knowledge about hearing and how the human brain interprets sound.
Insofar as electronic circuits are concerned, there are problems with measurement methods there too. In principle it should be possible to completely characterize the performance capabilities of all analog circuits. But in practice, many methods have been inherited from a prior era a long time ago when those measurement standards were more meaningful than they are today because they were adequate to reveal gross differences in equipment. As an example, the measurement of audio amplifiers at one watt output into a resisitive load is absurd as it has nothing to do with its real world use today. (Maybe it did in 1930.) Performance at representative power levels up to rated power with reactive loads including those that are not even passive which reflects what a loudspeaker load imposes would tell us a lot more and explain performance differences that current measuring standards can't. For example, testing FR at full power would obsolete the concept of TIM because it would be obvious that this type of distortion is the result of insufficient bandwidth at high power levels.
The implication that differences can't be measured and the trotting out of selective measurements to advertise a particular product is a marketing ploy, not a scientific tool. Also, it is usually not possible to describe performace with a single number such as the horsepower of an automobile engine. Real understanding comes from assembling many different characteristic parameters at the same time to develop a coherent if complex picture. It means that the best choice of what to select can depend on exactly how it is used. It also means that once required performance criteria are sufficient for a particular system design, further improvement is of no usable benefit. This seems to me to run contrary to what many audio hobbyists believe and what those who market to them would like them to believe.
Ever onward.
By 1968, I was happy at Ampex, but I transfered to an opening in the Audio department! Audio at last! There, I found less than the best engineers, who were in the instrumentation, video, and research departments. Still, I had a wonderful company library and access to 'experts' down the hall.
During this year, one of my best, I learned tape recorder design, servos, and what was wrong with current designs at Ampex with audio tape recorders. I then left audio for political reasons (my favorite boss was demoted) and I moved to the Research Division to make transport control electronics. I had hoped that the new transport could be used for audio mastering, but it was not to be, so I left Ampex completely (big mistake) to go into business with a small audio company, that also did sales and repair of hi fi equipment. After a few months of this, I realized that I was repairing and selling, not designing much, so I wanted to move on. It is now early 1970.
An old friend of mine, that I met at Ampex, was working for the Grateful Dead and wanted to hire me. So, without any other real alternative, I went to work for Alembic Inc, a small part of the GD family. I was initially assigned to make a solid state mixer to replace the relatively successful tube electronics that they were using. On the side, I decided to take some engineering courses at UC Berkeley, as I lived nearby. What a goldmine! Great professors, like Dr's R.G. Meyer and Don Pederson, who passed out class notes that they would write texbooks from. This is where I got my 'senior year' in EE design, unfortunately limited to linear and non-linear analog design. This leaves 'holes' in my education that can be taken two ways. One, that I can't easily design digital circuits, for example, but on the other hand, I am not 'duped' into thinking that something is either 'impossible' or 'perfect'. more later
By 1968, I was happy at Ampex, but I transfered to an opening in the Audio department! Audio at last! There, I found less than the best engineers, who were in the instrumentation, video, and research departments. Still, I had a wonderful company library and access to 'experts' down the hall.
During this year, one of my best, I learned tape recorder design, servos, and what was wrong with current designs at Ampex with audio tape recorders. I then left audio for political reasons (my favorite boss was demoted) and I moved to the Research Division to make transport control electronics. I had hoped that the new transport could be used for audio mastering, but it was not to be, so I left Ampex completely (big mistake) to go into business with a small audio company, that also did sales and repair of hi fi equipment. After a few months of this, I realized that I was repairing and selling, not designing much, so I wanted to move on. It is now early 1970.
An old friend of mine, that I met at Ampex, was working for the Grateful Dead and wanted to hire me. So, without any other real alternative, I went to work for Alembic Inc, a small part of the GD family. I was initially assigned to make a solid state mixer to replace the relatively successful tube electronics that they were using. On the side, I decided to take some engineering courses at UC Berkeley, as I lived nearby. What a goldmine! Great professors, like Dr's R.G. Meyer and Don Pederson, who passed out class notes that they would write texbooks from. This is where I got my 'senior year' in EE design, unfortunately limited to linear and non-linear analog design. This leaves 'holes' in my education that can be taken two ways. One, that I can't easily design digital circuits, for example, but on the other hand, I am not 'duped' into thinking that something is either 'impossible' or 'perfect'. more later
Moving on to the end. After a number of projects in the film industry, I went back to the GD to help do the 'Wall of Sound' in late 1972. At this time, I took the graduate equivalent of the courses taught by Meyer and Pederson on analog design. This essentially concluded my education. My experience, of course, continued, but by this time, I had studied electronics, loudspeakers, recording, film sound processing, and a little computer aided design. The only products that I designed at this time, that might be known to audiophiles, were the Levinson JC-1 (patented) and the JC-2 (world famous). The rest is of little or no concern here. I hope that this explains why some Ph'D types find me rather backward, yet others learn from my giving practical knowledge on audio design, here, and elsewhere.
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Steve,
I trust this is your sense of humor showing.
The argument presented in those test is that the AP System 2 Cascade is the ultimate measuring instrument, therefore if it does not show up on this set of tests it cannot be a problem.
I just got the notice the System 2 is discontinued and the newer stuff has resolution this is a bit better than 112db.
So if the form of distortion is an increase in signal related noise, using the averaging function to get better resolution will not easily show it. There are of course other measurements and techniques that can be used to look below the noise floor or at other interesting tidbits that the System 2 is not designed to view.
But of course the real question is if you are using instrument "X" to test audio cable what is it wired with inside?
ES
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